1. Field of the Invention
The present invention relates to a moving picture coding method and apparatus for coding a moving picture and a moving picture coding program.
2. Description of the Related Art
In recent years, the transmission and reception of the moving picture have been made through a network such as the Internet. When the moving picture is transmitted or received through the network, a process of compressing the moving picture is performed on the transmission side.
Of the processes on the transmission side, a quantization process comprises a process of dividing the DCT coefficients that are obtained by performing the DCT (Discrete Cosine Transform) for the moving picture data. Therefore, the quantization process has a great processing load, and various methods for relieving the load of the quantization process have been conceived.
For example, in Japanese Patent Laid-Open No. 10-191334 and Japanese Patent Laid-Open No. 10-116267, there was disclosed a method for relieving the processing load on the whole by skipping the division in the quantization process in predetermined instances.
In these methods, before the quantization process, a determination is made whether or not all the DCT coefficients contained in the block are zero in the quantization process, and if it is determined that they are all zero, the quantization process is skipped.
For example, supposing that “x” is the DCT coefficient to be quantized, “K” is the divisor based on the quantization parameter, and the arithmetical operation in the quantization is x/K, “y” obtained by the expression y=x/K, is determined as y=0 in a range −K<|x|<K, without making the division. In this case, the figures below the first place of decimals in the division result are discarded.